We knew it was coming, but today will be an historical day. Today Yahoo officially closes Yahoo Site Explorer. Most of the Site Explorer functionalities will be returning in Bing Webmaster Tools.
However, one of the main reasons people used Site Explorer is the link-data: who links to what site. That specific element will not return at Bing.
Yahoo announced the official date on her blog saying:
“With the completion of algorithmic transition to Bing, Yahoo! Search has merged Site Explorer into Bing Webmaster Tools. Webmasters should now be using the Bing Webmaster Tools to ensure that their websites continue to get high quality organic search traffic from Bing and Yahoo!. Site Explorer services will not be available from November 21, 2011.”
It is a natural follow up of the transition to Bing, who now needs to be pushing their Webmaster Tools so people will get used to that.
For link data we now have to depend on third party tools like Majestic SEO. Not a bad thing, but information straight from a search engine is valuable too.